Electric switch



Feb. 5, 1957 M. WIBELL ET AL. 2,780,690

ELECTRIC SWITCH Filed Oct. 14, 1954 3 Sheets-Sheet 1 Fig].

i f; WiTNESSES: INVENTQRS r Ralph 8.1mmel 4 and Mcriin WibelL BY ATTORNEY Feb. 5, 1957 M. WIBELL ETAL 2,

ELECTRIC SWITCH Filed Oct. 14, 1954 s Sheets-Sheet 2 Fig.3.

WITNESSES: INVENTORS ATTORNEY Feb. 5, 1957 M. wlB ET AL 2,780,599

ELECTRIC SWITCH Filed 001;. 14, 1954 3 Sheets-Sheet 3 Fig.4.

wlTNEssEs; I 'IINgIIiINTORIS 0 p mme (477 and Martin Wibell.

BY 8% W; W

ATTORN EY United States Patent ELECTRIC SWITCH Martin Wihell and Ralph E. Immel, Williamsville, N. Y., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application October 14, 1954, Serial No. 462,236 9 Claims. (Cl. 200-67) This invention relates generally to electric switches and more in particular to electric switches wherein snap action is provided for contact operation.

Many switch applications, for example those used in motor reversing service, require switches capable of making a great number of operations without appreciable wear or without requiring replacement of parts. In control of a planer platen it is necessary that the platen be operated at high speed at least on the return stroke and frequently on the cutting stroke to obtain maximum productivity from the machine. In such service the limit switches are mechanically operated by dogs set adjacent the limits of the platen travel. These dogs operate cams or other mechanical devices on the switch to actuate the switch which, in the stated application, functions as a limit switch controlling reversing of the platen motor to reversibly drive the platen within the limits established by the dogs or stops.

The duty cycle in such an arrangement is rapid and must always be positive to rapidly decelerate, stop and accelerate the platen in a reverse direction of movement. Such service requirements are severe. The impact of the dogs on the switch impart relatively high shock loads and rapid acceleration of switch parts. Hence, to minimize the mechanical loads it is essential that the switch parts associated with and driven by the cams shall be of low inertia, yet such parts must be strong enough to have long life under such operating conditions. Additionally, the switch arm and switch contacts must have low inertia and yet be sufiiciently durable to provide a long life expectancy under rapid switching conditions.

Accordingly, one object of this invention is to provide an electric switch which is capable of rapid switching operations.

Another object of this invention is to provide an electric switch which is easily manufactured and assembled.

Further to the preceding object, it is an object of this invention to provide an electric switch for rapid and frequent switching service in which the parts are essentially self-aligning.

A further object of this invention is to provide an electric switch embodying lightweight fabricated parts.

Yet another object of this invention is to provide a cam operated switch embodying a toggle type mechanism in which the switch parts, including the cam actuated parts, have low inertia.

Still another part of this invention is to provide an electric switch for rapid switching service which has long life.

The foregoing statements are merely illustrative of the various aims and objects of this invention. Other objects and advantages will become apparent upon a study of the following disclosure when considered in conjunction with the accompanying specification in which:

Figure 1 is a plan view of an electric switch apparatus embodying the principles of this invention;

Fig. 2 is a sectional view taken on the line II-II of Fig. 1 and detailing certain of the switch actuating parts;

Fig. 3 is a sectional view taken on the line III-III of Fig. 1 illustrating the contact structure of the switch;

Fig. 4 is a sectional view taken on the line IVIV of Fig. 1 illustrating certain other details of the contact assembly; and,

Figs. 5 and 6 are respectively elevation and plan views of the contact bar which mounts the moving contacts of the switch assembly.

The switch assembly is mounted within a box generally designated 1. Such a box may be of molded insulating material or die-cast metal. The box 1 is provided with a sleeve bearing 3 extending through one wall thereof and a pedestal bearing 4 extending upwardly from its bottom. The bearings 3 and 4 are coaxially disposed and rotatably mount a shaft 6 which extends through the sleeve bearing 3. A suitable cam 7 which is clamped or otherwise secured to the overhanging end of shaft 6 by means of a screw 8. The cam 7 may be actuated by any suitable mechanical means, for example, the dogs discussed hereinabove in connection with the application of this switch assembly in reversing the motor of a planer platen.

Shaft 6 is secured against axial movement by means of a stop bracket 10 which is secured to a flat surface provided on the upper side of bearing 3. Two screws 12 are utilized to secure the bracket to prevent angular movement thereof. The bracket 16, as seen in Fig. 1, is provided with 2. depending section 14 provided with a forked lower extremity 16 which straddles a circumferential groove 18 in the shaft 6. The depending portion of the bracket 14 is of generally U-shaped cross section and is provided with outwardly flanged upper side portions 20 which constitute stops defining the limits of angular movement of the shaft 6. Cooperating with the stops 20 is a tubular pin 22 which is press fitted into a suitable hole in the shaft 6. The upwardly projecting portion of the pin 22, as seen in Fig. 1, engages the stops 20 to thereby limit the extent of rotative or angular movement of shaft 6.

A switch arm 24 which is shaped from a single piece of sheet material is rotatably mounted upon the shaft 6. This switch arm is of the general configuration illustrated in Fig. 2 comprising a pair of laterally spaced side frame members 26 (see Fig. l) which are interconnected by an integral sheet metal web 28 shown in section in Fig. 2. This contact arm or switch arm 24 is preferably fabricated from thin spring steel or beryllium copper to keep the weight of this assembly at a minimum and additionally to provide a degree of resilience which will enable the assembly to endure the class of service to which it is subjected. Stability of the side frame members is achieved by fianging the marginal edges thereof, as seen in Figs. 1 and 4, to provide the required degree of stiffness of this portion of the mechanism.

A toggle link actuator 36 which is also formed of thin sheet material and which is of generally U-shaped configuration in cross-section, as best seen in Fig. l, is rotatably mounted on the shaft 6 in a position between the side frame members 26. Actuator 3%) is shown with the bight portion 32, which is integrally connected with the legs thereof, on the upper side of the shaft 6. This actuator is loosely connected to the shaft 6 by means of a tubular pin 34 which clears through a sloppy clearance hole 36 in the bight portion 32 of the actuator and is press fitted into a suitable hole in the shaft 6. A tube 38, functioning as a spacer, is fitted over the shaft 6 between the legs of the actuator thus stabilizing the legs against axial displacement along the shaft 6.

The free extremities of the side frame members 26 of i h arm 24 re iq ned by m an o a an e b acke 40 having end extensions 42, as best seen in Fig. 4, which clear through suitable slots in the webs of the side frame members 26 adjacent their free extremities. The angle bracket may be secured against displacement from the slots by spot welding or other suitable means if needed.

As seen in Fig. 2 one side 44 of the angle bracket 49 extends downwardly and is provided with a V-shaped depression 46 adapted to receive an edge 48 of a spring holder 50. The V-shaped depression and the edge 48 of the spring holder 50 constitute a knife edge bearing. A second spring holder 52 is pivotally connected by means of a pin 54 to the toggle linkage actuator 30. The respective spring holders 50 and 52 are provided with spring seats 56 and 58 and a compression spring 60 is compressed therebretween. Each spring holder is further provided with a laterally disposed extension arm respectively designated 62 and 64. These extension arms are bent towards each other to meet at their free extremities and arm 64 is provided with a slot 68 which receives the reduced end portion 70 of arm 62 to form a loose pivotal connection therebetween. This connection of the extremities of the extension arms 62 and 64 stabilizes the spring holders against tilting under the force of compression spring 60 thereby preventing the spring from being dislodged by tilting of the spring holders. At the same time, this loose pivotal connection permits relative angular displacement between the spring holders as the actuator is driven counterclockwise from its position shown which drives the pin 54 overcenter to the toggle position on the bottom side of a centerline between the axis of shaft 6 and the'knife edge bearing on the angle bracket 40.

A contact bar 66 of electrical insulating material is secured to the bottom side of angle bracket 40 by means of a spring loaded bolt 69. The contact bar is provided with a recess 71 in its upper face which straddles the side frame members 26 of the switch arm assembly. The bottom face of the recess 71 is sufliciently convex to engage and seat against the adjacent face of the angle bracket 40. With this arrangement the contact bar may tilt about its bearing point against the angle bracket to provide positive contact alignment and seating.

As best seen in Figs. 3 and 4, contact bar 66 is provided with longitudinally disposed slots 72 which open through each of its extremities. These slots occupy positions in planes substantially paralleling the axis of the shaft 6 and the slot faces, as seen in Fig. 3, are of con vex configuration. Slots 72 are adapted to receive respec-tive fiat leaf spring members 74 and 76 which are of electrical conducting material and which have respective pairs of contacts 78 and 80 mounted at their respective extremities. These assemblies form bridging contacts which cooperate with respective pairs of lower stationary contacts 82 and 84. The stationary contacts are mounted in suitable electrical insulating contact bases and are electrically connected to suitable terminals through which external connections to the switch may be made.' For instance, as seen in Fig. 3, the contacts 82 are connected to respective terminal straps 86. Similar pairs of upper stationary contacts may also be provided. For example, cooperating with a pair of movable contacts 78 there may be provided a pair of stationary upper contacts 88 connected to suitable terminal straps provided with screws 90 through which the electrical connections may be made, this appears in Fig. 3, and similarly an upper pair of stationary contacts 92 (only one of which is shown) may be provided to cooperate with the movable pair of contacts 80.

The assembly shown comprises four contact bases 94 for supporting the respective pairs of stationary contacts. These contact bases are identical in configurationand are provided with suitable mating faces whereby the upper base maybe inverted upon the lower base and secured therewith to the base by means of bolts 96 which clear through the contact base sections 94 and threadedly engage suitable tapped holes in the base 1.

in operation, when the shaft 6 is rotated by the cam 7, or by other suitable means, the actuator 30 is also rotated by means of the tubular pin 34 which is secured in the shaft. The toggle spring 60 is steadily compressed and when the pin 54 on the actuator goes overcenter a suiticient distance the insulating cross bar or contact bar 66 is quickly snapped from its lower to its upper position. The travel of the movable contact bridges is limited by the separation of the upper and lower stationary contact pairs. The loose or sloppy fit between the actuator and the tubular pin 34 prevents the contact arm or switch arm 24 from being held once it starts to move. It will be appreciated that all moving parts are designed for maximum strength and minimum weight. Rigidity of the thin sheet metal parts, where needed and in the degree needed, is achieved by flanging the edges. Lightness of weight and some flexibility are essential to provide a satisfactory mechanical life. The provision of the convex spaces defining the slots 72 permits the contact bridges to rock and deflect in the slots whenever the movable contact bridges begin to engage the cooperating stationary contacts. Thus, the movable contacts may perfectly align themselves with the fixed stationary contacts up to and including the limited movement of the switch arm.

Although but one embodiment of this invention has been illustrated in the drawings and described in this specification, it will be appreciated by those skilled in the art that various changes may be made in the arrangement illustrated, both as to its details and as to the organization of the parts, without departing from the spirit and scope thereof. Accordingly, it is intended that the foregoing disclosure and the showings made in the drawings shall be considered only as illustrative of the principles of this invention and not interpreted in a limiting sense.

We claim as our invention:

1. A toggle switch comprising, a rotatably mounted shaft, means for limiting rotative movement of said shaft between given angular positions, an actuator loosely connected to said shaft to rotate therewith, a switch arm pivotally mounted on said shaft, a stationary contact, a moving contact mounted on said switch arm at a point displaced from the axis of said shaft such that engagement of said moving contact with said stationary contact occurs upon movement of said switch arm in a direction towards said stationary contact, a pair of spring holders, each having a spring seat and a laterally disposed arm, means pivotally mounting one spring holder at a point on said switch arm displaced from said actuator, with said spring seat facing said actuator, means pivotally mounting the other of said spring holders on said actuator for movement with said actuator back and forth across a centerline between the axis of said shaft and the point of pivotal mounting of said one spring holder, a compression spring mounted between said spring seats, and means pivotally connecting said laterally disposed arms adjacent their extremities.

2. A toggle switch comprising, a rotatably mounted shaft, means for limiting rotative movement of said shaft between given angular positions, an actuator secured to said shaft to rotate therewith, a switch arm rotatably mounted on said shaft, a stationary contact, a moving contact mounted on said switch arm 'at a point displaced from the axis of said shaft such that engagement of said moving contact with said stationary contact occurs upon movement of said switch arm in a direction towards said stationary contact, a pair of spring holders respectively pivotally connected to said actuator and to said contact arm, each spring holder having a spring seat and a laterally disposed arm, a compression spring disposed between said spring seats, said laterally disposed arms straddling the length of said compression spring and being pivotally connected at their free extremities, said point of pivotal connection of one spring holder to said actuator being at a point on said actuator which moves back and forth across a centerline joining the axis of said shaft and the point of pivotal mounting of the other spring holder, with movement of said actuator between said given angular positions to provide toggle operation of said contacts.

3. A toggle switch comprising, a rotatably mounted operating shaft, means for limiting rotative movement of said shaft between given angular positions, a switch arm comprising a pair of interconnected laterally spaced frame members rotatably mounted on said shaft, a cross bar of electrical insulating material connected between said switch arm frame members adjacent the free extremities thereof, a contact assembly comprising a movable contact connected to said cross bar to move therewith and a stationary contact disposed in the path of movement of said movable contact to be engaged thereby, a toggle linkage actuator connected to said shaft to rotate therewith, said actuator being disposed between said switch arm frame members, a pair of spring holders respectively pivotally mounted on said actuator and on said cross bar and having respective spring seats disposed in confronting relation, a compression spring compressed between said spring seats, each spring holder having a later ally disposed arm, and means pivotally engaging the free extremities of said laterally disposed arms.

4. A toggle switch comprising, a rotatably mounted shaft, means for limiting rotative movement of said shaft between given angular positions, an actuator rotatably mounted on said shaft, a pin loosely securing said actuator to said shaft providing limited relative angular movement therebetween, a switch arm rotatably mounted on said shaft, a stationary contact, a moving contact mounted on said switch arm at a point displaced from the axis of said shaft such that engagement of said moving contact with said stationary contact occurs upon movement of said switch arm in a direction towards said stationary contact, a pair of spring holders respectively pivotally connected to said actuator and to said contact arm, each spring holder having a spring seat and a laterally disposed arm, a compression spring disposed between said spring seats, said laterally disposed arms straddling the length of said compression spring and being pivotally connected at their free extremities, said point of pivotal connection of one spring holder to said actuator being at a point on said actuator which moves back and forth across a centerline joining the axis of said shaft and the point of pivotal mounting of the other spring holder, with movement of said actuator between said given angular positions to provide toggle operation of said contacts.

5. A toggle switch comprising, a rotatably mounted shaft, means for limiting rotative movement of said shaft between given angular positions, a switch arm comprising a pair of interconnected laterally spaced frame members rotatably mounted on said shaft, a cross bar of electrical insulating material connected between said switch arm frame members adjacent the free extremities thereof, a contact assembly comprising a movable contact connected to said cross bar to move therewith and a stationary contact disposed in the path of movement of said movable contact to be engaged thereby, a toggle linkage actuator rotatably mounted on said shaft between said switch arm frame members, a pin loosely securing said actuator to said shaft providing limited relative angular movement therebetween, a pair of spring holders respectively pivotally mounted on said actuator and on said cross bar and having respective spring seats disposed in confronting relation, a compression spring compressed between said spring seats, each spring holder having a laterally disposed arm, and means pivotally engaging the free extremities of said laterally disposed arms.

6. A switch assembly comprising a rotatably mounted switch arm, means for angularly moving said switch arm, a contact bar of electrical insulating material mounted on the free extremity of said switch arm, said contact bar being disposed laterally of said switch arm, said contact bar having a slot adjacent an end thereof in a plane substantially paralleling the axis of rotation of said switch arm, the confronting faces of said contact bar defining said slot being convex about an axis substantially paralleling the longitudinal axis of said contact bar, a bridging contact member comprising a fiat spring member of electrical conducting material having contacts at each end, the central portion of said flat spring member being fitted between said convex faces with the longitudinal axis of said flat spring member substantially paralleling said switch arm, and a pair of stationary contacts respectively disposed in the path of movement of the respective contacts on said fiat leaf spring.

7. A switch assembly comprising, a switch arm unit having a pair of laterally spaced frame members, means interconnecting said frame members adjacent one end, a shaft rotatably mounting said frame members adjacent said one end, means for angularly moving said switch arm unit, a contact bar of electrical insulating material straddling the free ends of said frame members and secured thereto to be actuated thereby, the respective ends of said contact bar having slots opening through the ends thereof which lie in planes substantially paralleling the axis of said shaft, a pair of bridging contact members respectively comprising a fiat spring member of electrical conducting material having a contact at each end, the central portion of each fiat spring member being fitted into the corresponding one of said slots, the confronting faces of said slots being convex, means securing each spring member in its slot with the longitudinal axis of said spring member substantially paralleling the longitudinal axis of said switch arm unit, and respective pairs of stationary contacts disposed in the path of movement of said movable contacts to be engaged and bridged thereby.

8. A toggle switch comprising, a rotatably mounted operating shaft, means for limiting rotative movement of said shaft between given angular positions, a switch arm comprising a pair of interconnected laterally spaced frame members rotatably mounted on said shaft, a cross bar of electrical insulating material connected to and straddling the free extremities of said switch arm frame members, the extremities of said contact bar being provided with longitudinally disposed slots in planes substantially paralleling the axis of said shaft, said slots being defined by convex confronting faces, a pair of movable bridging contact members, each bridging contact member comprising a flat spring member having contacts at its extremities, said fiat spring members being secured in said respective slots, two pairs of spaced stationary contacts disposed to be bridged by said bridging contact members, an actuator rotatably mounted on said shaft, means loosely connecting said actuator to said shaft providing limited relative angular movement therebetween, a pair of spring holders respectively pivotally connected to said actuator and to said contact bar and having respective spring seats disposed in confronting relation, a compression spring compressed between said spring seats, each spring holder having a laterally disposed extension, and means pivotally connecting the free extremities of said spring holders.

9. A toggle switch comprising, a rotatably mounted operating shaft, means for limiting rotative movement of said shaft between given angular positions, a switch arm comprising a pair of interconnected laterally spaced frame members rotatably mounted on said shaft, a cross bar of electrical insulating material connected to and straddling the free extremities of said switch arm frame members, the extremities of said contact bar being provided with longitudinally disposed slots in planes substantially paralleling the axis of said shaft, said slots being defined by convex confronting faces, a pair of movable bridging contact assists members, each bridging contact member comprising a fiat having a laterally disposed arm extending toward the spring member having contacts at its extremities, said other, and means pivotally connecting said laterally disflat spring members being secured in said respective slots, posed arms adjacent the free extremities thereof.

two pairs of spaced stationary contacts disposed to be bridged by said bridging contact members, an actuator 5 References Cted mthe file of fills Patent secured to rotate with said shaft, a pair of spring holders UNITED STATES PATENTS respectively pivotally connected to said actuator and to 2,326,) 11 Currie Aug 3, 1943 said cross bar, and each having respective spring seats disposed in confronting relation, a compression spn'ng 10 FOREIGN PATENTS- compressed between said spring seats, each spring holder 751,674 France June 26, 1933 

